Accessibility is the term used to describe whether a website can be used by people of all abilities/disabilities on a range of differing digital devices.
The way a person perceives information is affected by their ability/disability along with how they navigate between website pages. A website can only be classed as accessible if all people, including the elderly and disabled, can use it.
The BBC provides a comprehensive guide covering how to get the most of the accessibility features and assistive technologies available for your computer, operating system, and web browser.